Machine for feeding and inserting screws



May 13, 1952 w. M. PHELPS 2,596,958

I MACHINE FOR FEEDING AND INSERTING SCREWS Filed Sept. 1, 1948 6 Sheets-Sheet 1 I62 FIG. I.

ATTOR N EY May 13, 1952 w. M. PHELPS 2,596,958

MACHINE. FOR FEEDING AND INSERTJKIG SCREWS Filed Sept. 1, 1948 v e Sheets-Sheet 2 3mm WILLIAM M, PHELPS @MWE ATTOR N EY May 13, 1952 'w. M. PHELPS H 2,596,958

MACHINE FOR FEEDING AND INSERTING SCREWS Filed Sept. 1, 1948 v e Sheets-Sheet 3 WILLIAM M, PHELPS ATTO R N EY May 13, 1952 w. M. PHELPS 2,596,958

MACHINE FOR FEEDING AND INSERTING SCREWS Filed Sept. 1, 1948 '6 Sheets-Sheet 4 Fl G. I8

a"! as 58 3 g 41 92 y 4 29 E 85 ea 69 n z 29 2 E g m v 8 74 l l\\ I 3s 137 371' l8 I15 3s I I48' 39- I49 F G. M C) O I48 3M 49' WILLIAM M.PHELP-S I50, I: I so ATTO R N EY 1' I952 v w. PHELPS 2,596,958 7 MACHINE FOR FEEDING AND INSERTING SCREWS Filed Sept. 1, 1948 6 She ets-?She et 5 5;; vol 0?: I. 'zo -el- J ATTOR N EY WILLIAM M. PHELPS K May 13, 1952' w. M. PHELPS MACHINE FOR FEEDING AND INSERTING SCREWS Filed Sept. 1, 1948 6 Sheets-Sheet 6 21 m WILLIAM M.PHELPIS Fla.

. ATTORN EY Patented May 13, 1952 MACHINE roareanme INSERTING e soasws William M. Phelps,-Chatsworth; Ga assignor, by?

mesneassignments, to Chatsworth' Manufac turing Co'., chatsworth, ,Gla.,, ,a--- corporation of Georgia ppli ation-Se t mb r 1,119 8,Serial N 71285;.-

Claims.

My invention-relates to amachine for inserting screwsineiectrical outlet boxes and the like An important object of the invention is to provide av machine, having, means for feeding. a plurality of machine screws to a revolving spindle,lwhere thescrewsare individually resiliently held and rotated, so that they may be inserted intoscrew threaded openings of outlet boxes.

A'further object is to provide a screw inserting machine having novel means for forcing the screws, one at a time,.from'the revolvingspindle.

Affu'rther object'is to provide a machineof the above, mentioned character adapted to handle screws of two. different sizes; and to apply one size ofiscrew downwardly into the work and the other ,sizegupwardly; j

A further object is to provide a'machine of the above mentioned character which is extremely simple,' compa c.t and sturdy, the'machine being adapted for insertingscrews into a wide variety of work.

Otherobjects-and advantages of the invention'will be apparent during thecourse of the following description.

In the accompanying drawings, forming a part of this. application, and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is, airont'elevationofthemachine embodying the invention,

Figure 2 is an end'elevation of the same,

Figure" 3 is a plan-view ofthe machine,

Figure 4 is a vertical secti'ontaken on line 4-5 of Figured, parts broken away,

Figure 5 is a fragmentary vertical section taken on line 5--5 'of Figure 3,'parts omitted,

Figure 6* is 'avertical section taken on line 6--6 'of' Figure 5,

Figure '7 isa fragmentary side elevation of one screw-inserting spindle and associated elements asyieWed-fr'om the left in Figure '3,

Figure B is a fragmentary centrally vertical section through the spindle shown in Figure 7, parts in elevation,

Figure 9 'isan enlarged of screw gripping jaws,

FigurelO-is a vertical section taken on line I I -40 0f: Figure 9,

Figure 11 is=a side elevation of. a screwgripping and inserting spindle;

fragmentary plan view shifted vertically there1n,.1sa =rec1procatory bar Figure '12 "is 'a horizontal 'section taken on line Figure 13" isa bottom end elevation of the spindle in Figure -11,

Figure 14 is'a-transverse vertical section taken on line l4'- I l of Figure. 3, parts omitted,

7 Figure" 1.

Figure; 15 is a yer-tic l section takenijonj line IE-L-l 5 of Figure. 3,, parts -omitted-,;,

Figure 16, is anenlarged, central vertical, section through 1 a, screw gripping and inserting spindle, parts broknawiy,

Figure 17 isiranlenlarged. plan View, oi-gai-re'st and. associated elements, and,

Figure 18 is ,a -vertical section taken ,onjjlirie M 8 of Figure 17.

In thedr'awingswhere' forthe purpose ofillustration is shownga preferred embodiment' of my inventiomthe numeral .20 designates'a horizontal workbench or 'ta'blehaving front and rear pairs of legs- 2| and: 22.: Rigidly mountedupodthe table near the forward edge-of the same 'an'dfnear its right end, Figure'3;:is arigid 'L-shapedbracket 23 having a vertical arm 24' extending "above the top of the tablefor a substantial distance, A

horizontal bolt ,or shaft 2fi-"is secured-tothe arm per 39 is"provided in-"its side with arectan'gular opening-30; and-a hinged '-'door --or cover 3l' is provided for the openings The 'axis of'th'e-conicai hopper 301s horizontal and' the "hopper tapers outwardly toward theright' end of the-table '20, The axis of the hopper 3E, is disposed a substantial: distance above the top I of the: table such as one foot, although: this distance may vary" with the" sizeof the machine. Ri'gidly mounted upon the top ofthe table 29 near the right 'endv of .the same; Figure e and'slightly rearwardly- Of;th6 bracket 23;. is;- a':vertica1; support-or tube 33 the upper-endof which-is disposedsubstantially-at the elevation 'of the horizontalaxis of the i-shaft 25, 'as' shown. I Slidably mounted Within the tube 33, andadapted to be shiftable'rod 35B; The rodtii-extendsdown wardly behindthe' adjacent front legit, and" is pivotally connected at "itslower end 'to a'io'ot lever 40; pivotally connected at-M to the adjacent rear leg '22, near the lower endof the same.

The foot lever G6 extends forwardly of the front legs 21 and carries a pedal plate 42, rigidly secured thereto. A retractile coil spring 53 has its lower end connected to the lever 59 adjacent to rod 39, and its top end connected to a bolt 4 mounted upon the upper portion of the adjacent leg 2|. The spring 43 serves to hold foot lever 58 upwardly, and to maintain the bar 34 in its uppermost position. Rigidly mounted upon the inner side of the leg 2! adjacent to the foot lever 40 is a vertical guide bar or strap 45, having upper and lower lateral ends 46. The foot lever Ml operates between the inner side of the leg 25 and strap 45, and has its vertical swinging movement limited by the lateral ends 56. Rigidly secured to the bar or plunger 34 near the upper end of the same is a forwardly proiecting head or block 41. Rigidly secured to the block 4! near its forward end is a depending pin or plunger 43, secured in place by means of set screws 49, or the like, and by means of which the pin 48 may be adjusted vertically with respect to the block 4'5. The pin 48 is shiftable vertically, and is disposed at right angles to the horizontal axis of the hopper 30 and intersects this axis.

Between its ends, the tube 33 has mounted upon it a T-fitting including a horizontal forwardly projecting arm 55. The arm 5i is connected through a short pipe 52 with a forward T-fitting 53, forming a stationary support or bearing for a vertical rotatable tubular spindle 54. Rigidly mounted within the T-fitting 53 is' a bushing 55, the vertical bore of which rotatably receives a tubular shank 56 of the spindle 5i. Rigidly mounted upon the shank 56 by means of countersunk set screws 51, and adapted to rotate with the spindle, is a horizontal grooved pulley 58. The pulley 58 serves as a thrust bearing to hold the spindle 54 against axial movement, and this pulley operates in a deep horizontal slot 59 formed in the forward side of T-fitting 53. The spindle 54 is provided near its lower end, and below the bushing 55, with an enlarged cylindrical head 60 carrying an annular group of spaced elongated depending rigid fingers or prongs 5!,

.integral therewith, and forming narrow vertical passages or slots 6| therebetween. The spindle 54 has a central cylindrical bore 62 extending entirely through the shank 56, head 60 and fingers 6|. are preferably conically tapered toward their lower free ends, as shown. The narrow slots 5! extend from the bottom tips of the fingers 6| to the bottom of the enlarged head 60, and in axial alignment with the slots 5!, thehead 6B is provided in its outer cylindrical surface with a plurality of axial grooves or recesses (33. Seated within the axial recesses 63 is a plurality of resilient gripper prongs or fingers 64, which are bent inwardly at the bottom of head 6'6 for forming straight downwardly converging resilient portions 65 disposed within the slots El, and arranged between the rigid fingers 6|. The portions 65 are biased radially inwardly with respect to the fingers 6|, Figure 16, and form inclined gripping elements to resiliently hold each screw 66 as it is fed downwardly through the bore 52 to the lower end of the spindle 54. The resilient prongs 64 are preferably formed of heavy spring steel wire, or the like. The prongs 66 are rigidly secured within the recesses 63 by means of set screws 63', which engage in screw threaded openings in an annular ring or collar 64' mounted upon and surrounding the head 69. The set The outer surfaces of the fingers GI' v pivot screw '5 l.

4 screws 63 also serve to secure collar 64 to the head.

Rigidly mounted upon the top end of T-fitting 53 is a stationary head 67, provided in its inner side and top with a vertical slot 68, leading into a cylindrically curved end 69, in axial alignment with the bore 62. The slot 68 is wide enough to receive the heads of the screws 66 therein, and the diameters of the bore 62 and end 69 are such that the heads of the screws may pass through such bore and end. Rigidly mounted, upon the top of head 61 is a block 10, carrying a vertical Slidably mounted upon the tops of block it and head 61 is a pair of opposed relatively thin fiat gripping jaWs TZ. Each jaw i2 is provided in its outer end with a horizonal circularly curved recess 13, forming a seat for a U- shaped spring "l4, surrounding the outer ends of the jaws. The inner ends of the spring M carry inwardly projecting lateral extensions (5, arranged within openings iii in the outer sides of jaws 12. The spring M serves to maintain the jaws i2 biased closed at their inner ends, or at the left in Figure The inner side of each jaw 72 is cut away near its outer end, forming diverging shoulders '11, providing lateral clearance to permit the inner ends of the jaws to swing open. Eachjaw I2 is provided in its inner end and side with a notch 1'8, the longitudinal sides '23 of which diverge slightly, Figure 9. The ends 89 of notches 18 are circularly curved, as shown, and the sides 19 and ends 35 are inclined and converge downwardly, Figure 10. The notches l8 are disposed opposite each other and form a seat 8! for the heads of the screws 66 that move down a slide 84. The inner edges of the jaws 12' also have circularly curved recesses 82 to engage about the pivot screw H. The spring 14 maintains these recesses 82 in engagement with the pivot screw 1 l. A stop screw 83 is mounted upon the head 67, between the pivot screw ll and notches l8, and serves as a stop to limit the inward or closing movement of the same.

Rigidly mounted upon the top and left side of the headE'l, Figure 4, and extending laterally thereof, and into the conical hopper 35, is the inclined guide or bar 84. The free end of the inclined guide 84 is disposed close to the inner face of disc pulley 26, and is spaced slightly below the top of the hopper 363, Figure 4. The guide 84 is provided with a central vertical longitudinal narrow slot 85 extending throughout its entire length, and leading into the wider slot 68. The slot 85 is of suflicient width to accommodate the screw threaded shanks of the screws 66, but is narrow enough to prevent the heads of the screws from entering the slot. The end 69 and bore 62 are of sufficient diameter to accommodate the heads of the screws 65 with enough clearance to permit the free movement of the screws through such end and bore. The top end of the inclined guide 84 is provided with a cap or seat 86, rigidly mounted thereon, and having a transversely curved recess 87 extending longitudinally of the slide and forming a seat to receive the screws 66 dumped onto the slide 84 in a manner to be described. Rigidly secured to the inner surface of the disc pulley 26 is a lateral extension 8'! of a single flat radial bucket or vane 88, having its inner longitudinal edge 89 arranged parallel to the side wall of the hopper 38, as shown. The edge 89 is arranged close to the top of the seat 81, with enough clearance to permit the vane 88 to pass the seat and any screw 66 thereon without striking the same, as the hopper tionary annular collar I46 carrying a vertical post I41 disposed radially outwardly of the colla'r I43, and extending slightly above the top ends of the fingers I4I. Rigidly secured to the top of post I41 is a block or rest I48 the lower surface of which is arranged slightly above the upper ends of rigid fingers MI. The rest I48 is provided in its inner edge with a circularly curved recess I49 in axial alignment with the bore I42 and being of substantially the same .diameter. The rest I48 is provided in its top surface and upon opposite sides of the recess I49 with relatively shallow recesses I48, which are circularly curved in transverse cross section, Figure 18. The sides of the recesses I48 preferably converge slightly toward the inner edge of rest I48, Figure 17, and the recesses I43 are arranged near the inner edge of the rest, as shown. The rest I48 may serve as a seat or support for an electrical outlet box, or like work, into which screws I82 are inserted upwardly. It may be desired to apply a cable clamp I49 to the electrical junction box, simultaneously with the application of a screw I82 thereto. In this case the cable clamp I49 having spaced opposed cable receiving formations or crowns I58 is seated upon the rest I48, and the crowns I58 engage within the recesses I48, Figure 18. The clamp I49 has an opening II' which registers with the recess I49, Figure 18, so that a screw I82 may be partially ejected from the spindle I31, to project upwardly through the recess I49 and opening I5I. With the screw thus arranged within the opening I5I, the clamp I 48' will be held in place by the screw upon the rest I48, and the junction box may be brought into position above the screw and clamp so that the screw may be turned into the box by the spindle I31, for securing the clamp to the box. Rigidly mounted upon the lower end of the T- fitting I33 is a stationary block or head l58, preferably provided in its lower end with a transverse rectangular slot I5! for snugly receiving the top end I52 of a U-shaped conveyor tube I53, having a bore I54 through which the screws I82 may pass. The top end I52 is rigidly clamped in place within the slot I 5| by means of diametrically oppositely arranged set screws I55 carried by the head I58. The lowermost end of the U-shaped tube I53 preferably engages the top of table 28, Figure '7, and the opposite upper end I56 of the tube I53 is rigidly secured within a transverse rectangular slot I51 formed. in the bottom of head I23.

Rigidly mounted upon the table 28 near the rear corners of the same are upstanding posts or supports I58 carrying T-fittings I59 at their top ends, and adapted to serve as bearings for a horizontal rotatable shaft I68, journaled within the T-fittings or bearings I58. One end of the shaft I68 extends outwardly beyond the left end of the table, Figure 3, and has rigidly mounted upon its outer end a grooved pulley I 6|, receiving a belt I62, which engages the disc pulley 98 of the unit 94. Mounted upon the shaft I68 is a pulley I63, identical to the pulley NH, and in alignment with the disc pulley 26 of unit 93, Figure 3. The belt I64 engages the pulley I63 and associated disc pulley 28. Pulleys I65 and I96 also are rigidly mounted upon the shaft I68, in alignment with the pulleys I38 and 58 respectively. Belts I61 and I 88 engage the pulleys I 65 and I38, and I66 and 58, as shown. An electric motor I69 is securely mounted upon the table between the shaft I68 .and HI.

and unit 93. The armature shaft of this motor carries a pulley I18 in alignment with a large pulley I1I rigidly mounted upon the shaft I68. A drive belt I12 operatively connects pulleys I18 A motor switch I13 may be provided near the rightend of the table, Figure 3.

' The operation of the machine is as follows:

Referringfirst to the unit 93, which inserts the screws 66 downwardly through the revolving spindle 54, the hopper 38 is partially filledwith the screws 66 which are introduced through the hinged cover 38'. It is preferred to introduce several pounds of screws into the hopper but the number of screws may be varied. With the motor I69 operating and driving the shaft I 88, the hopper 38 revolves, and the radial vane 88 picks up the small number of the screws 65, which tend to remain at the bottom of the hopper, on each revolution, and carries these screws to the top of the hopper with the aid of centrifugal force. When the vane 88 is at the top of the hopper, Figure 4, and directly over the seat 86, the screws 66wil1 be dumped, and due to the law of averages, some of the screws will fall upon the seat 81 and enter the longitudinal slot 85, with their heads upwardly and supported by the inclined guide 84. The inclination of the guide 84 is such that the screws 66 will slide downwardly and enter the seat 8| formed by the recesses 18 of the jaws 12, having the inclined sides. The jaws 12 are held normally closed by the spring 14, and as one screw at a time enters the seat SI, it is supported or suspended above the bore 62 of the spindle 54, and is disposed within the slot 68. The operator now depresses the pedal 42 with his foot, moving the pin 48 downwardly. The pin engages the head of the screw being held between the jaws 12, and when this occurs the jaws will open, due to the action of the head of the screw upon the inclined surfaces of recesses 18, allowing the screw to drop into the bore 62 of the spindle 54 which is continuously revolving. As this process is repeated by the operator, the bore 62 will become partly filled with the screws 56, Figure 4, and the lowermost screw 66 will be resiliently held near and above the lower end of the spindle 54 by the gripper prong portions 55. When the next screw 66 enters the seat 8|, and the pin 84 moves downwardly for its full travel as limited by the extension 46, the lowermost screw 66 in the spindle will be partially ejected therefrom. The prong portions 65 will yield radially outwardly to permit the screw threaded shank of the lowermost screw to project beyond the lower end of the spindle 54 for approximately a quarter of an inch. The operator now brings the screw threaded opening of the electrical junction box, or other work, into engagement with the ejected end of the lowermost screw so that the screw may be turned into the screw threaded opening by the revolving spindle 54. As the screw enters the screw threaded opening in the work, the prong portions 65 yield further to permit the head of the screw to be drawn out of the lower end of the spindle. When this occurs, the next lowermost screw in the spindle will be held above the lower end of the spindle by the resilient prong portions 65 until another screw enters between the .iaws 12 and is pushed downwardly by the pin 48. When this occurs another screw is of course partially ejected at the bottom of the spindle, as previously described. The travel of the pin 48, as controlled by the extensions 46 of guide strap 45, is such that the lowermost screw age-cacao soon will be filled with screws so that no ad'dition'al screws can'- be accommodated :by it. E If :the hopper c'ontinues 'ito revolve while the slot 8 5 :isi'full rbfxscrewsnno: damage-mill; -be i done-to the. machine; as the additional screws 'dumped onto. the sIi'deL 8 iaawill :simplyfallback -intouthe m hopper.

The :operation ofr themnitr '94 substantially identical-with:;the iabove described ,operationv'of thexunit; 93, and; differs: onlyinthat the screws U-shaped conveyor tube l53 and upwardlyiinto thespindle 1'31. l The operator depresses the pedal H9 to operate the pin H0 in the same manner that the pin 48 zisropera-ted, the vertical movement of the pin H0 being properly limited by the st'rap 12L The function and purposebfthe jaw I28 are identical with thoseof' the jaws 'lii. Likewise, therunction ofetherotary hopper 98, guide 9a,and associated elements, is identical .to thatv .of the corresponding elements of the unit 93. TWhenlithe 'U-shaped tube. 2l-53-- andsspin'dle l3'leare partlyafilled with the screws lll2',.-by-=repeate'd'a'ctuations ofthe pinl'llLand onermore screw islforced ihto"the'headf-I.]Z5, betweenilthe jaws II 23, thenppermost screw? 1'02 in thespindle l3'imwilllbe. partially ejected, 'and-Ithe shankrof this. ,screw; .enters' "the recess 1 1'49 and projects slightly-tabovefthe rest T48, preferably for about a quarter or an inch. "The .workdsheld ,upon or slightlyabovelthe rest 118, so thatithe uppermost screw, Figure 8, may be turned into the work, The resilient prongs I function identically with the prongs 65, and further discussion of the operation of unit 94 is thought to be unnecessary. The operation of the unit 94 in connection with the application of the cable clamps I49 has been explained. I

It is thus seen that I have provided efficient, practical and rapid means for inserting screws upwardly and downwardly into various types of work. The machine is very sturdy, and there is little likelihood of any of the screws becoming jammed during their travel toward the'ends of the spindles 54 and I31.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. A machine for inserting screws comprising a non-rotatable support member having an opening to receive one screw at a time, a pair of pivoted gripping jaws arranged adjacent to the entrance of the opening and being resiliently biased closed and extending over the opening, the jaws being recessed to permit the passage of the shank of a screw into the opening of the support member but serving to hold the head of the screw so that it cannot enter the opening of the support member while the jaws are closed, a substantially vertical tubular spindle rotatably mounted beneath the support member for receiving screws from the opening of the support member one at a time, resilient means carried by the spindle near its lower end and engaging the lowermost screw within the spindle to yieldably hold the same while it is turned into work and 20 aresilient means Ltconnected -with the gripping releasingl'the screw iwhen'citis" "fully engaged with the :work a reciprocatory;nonerotatable. plunger arranged: above.- the:;sllpl orti-= member and jaws and engaging the head of each: 'SCIGWIihEld. by the jaws to force ;.the:screw downwardly into the bore .of the spindle, :v the. jaws: :then :1 spreading apart to. permitrtheq-p'assage of" the i screwvand plunger between same and closing automatically when the plunger is withdrawn, and stop: means connected with the :plunger to limitthe extent of itsdownwardmove'ment so that each-descent of the plunger'will shift the lowermost screw in the spindle into engagement with said :resilient means.

2. A- machinenfor inserting-screws comprising a non-rotatable support membenhaving an-opening. to receive screws; a #pairiofpivoted gripping jaws: arrangedadiacentrtoz the top of :the support membersand, extending I over :the-,:opening; thereof,

jaws to, maintain themaclosed,ttheclosed;.-jaws being recessed to provide an opening above the opening in.thesupportunember;'large enough to permit ,the shanks of--screws to :enter the opening oft-the. supportmembem but preventing: the; 'passage :of r-theinheads @into;thesamessaid "recesses iormingincli-ned facesftor-facilitate: opening the jaws; a substantially verticalitubular spindle rotatably' mountedabeneath the. support members-to receive screws therefrom, zi'esilientsmeans carried by the spindlesforengagement with ,the :lowermostascrewi within the-samaand, yieldably :holdings such. screweas -it...--is:turned,-.into works andl a reciprocatory ,inonr-rotatable ggpllllggel' =-rod arranged above rthe-sppport memberaand -jawsrand engaging- .the 1 {heads ofaeach screw 'held'rbya. the gripping jaws to force the same downwardly into the bore of the spindle, the action of the head of the screw on the inclined faces of the jaws causing the jaws to separate and permit the passage of the plunger rod between the same, the jaws closing automatically when the plunger rod is elevated above the jaws.

3. A machine for inserting screws comprising a, support member having a substantially vertical opening for receiving screws, gripping jaws mounted upon the support member to hold each screw over the opening of the support member and adapted to be opened so that the screws may enter the opening one at a time, a substantially vertical tubular spindle rotatably mounted beneath the support member for receiving the screws therefrom when the jaws are opened, the lower end of the spindle having a plurality of circumferentially spaced slots, inclined resilient prongs secured to the spindle and extending through the slots and having their lower ends projecting radially inwardly of the slots and into the bore of the spindle, the prongs engaging and resiliently holding each screw as it passes to the lowermost end of the spindle so that the screw can be fed into work, the prongs releasing each screw as it becomes fully engaged with the work, and a non-rotatable plunger arranged above the support member to engage each screw head held by the gripping jaws and force the same through the jaws and into the opening of the support member, whereby each lowermost screw is forced into engagement with said resilient prongs.

4. A machine for inserting screws comprising a non-rotatable support member having a substantially vertical opening to receive the screws, a pair of pivoted gripping jaws mounted upon the support member and extending over the top of the opening and being resiliently biased closed, the closed jaws being recessed to form an opening 1eading into the opening of the support member which will permit the passage of the shank of a screw through the closed gripping jaws but prevent the passage of the head of the screw therethrough, the recesses forming inclined faces, a rotatable tubular spindle having a substantially vertical bore operatively connected with the support member for receiving screws therefrom, resilient means carried by the spindle for engaging the screws near the discharge end of the spindle and resiliently holding the screws as they are turned into work by the spindle, and a non-rotatable reciprocatory plunger arranged above the support member and gripping jaws and engaging each screw held by the gripping jaws to force the same beyond the jaws and into the opening of the support member, the heads of the screws coacting with said inclined faces for s reading the jaws apart, the jaws closing automatically when the plunger is elevated.

5. A machine for inserting screws comprising a relatively stationary support member having a substantially vertical opening to' receive screws, a pair of pivoted gripping jaws mounted upon the support member above the opening and being resiliently biased closed, the closed jaws having opposed recesses forming an opening smaller than the opening of the support member and receiving the shanks or" screws but preventing the passage of their heads into the opening of the support member, a substantially U-shaped tube having one end connected with the support member for receiving screws therefrom, the other end of the U-shaped tube being upwardly directed so that the screws passing through the same from the support member, are fed upwardly, a rotary tubular spindle connected with the last-named end of the U -shaped tube for receiving screws therefrom, resilient means carried REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,598,447 Kleppinger Aug. 31, 1926 2,025,273 Dellaree Dec. 24, 1935 2,256,012 Blair Sept. 16, 1941 2,263,858 Borge Nov. 25, 1941 2,322,024 Hutchison June 15, 1943 2,373,992 Billinghurst Apr. 17, 1945 2,471,793 Stull May 31, 1949 2,506,835 Johnson May 9, 1950 2,534,140 Moore Dec. 12, 1950 2,544,165 Krasnow Mar. 6, 1951 2,554,732 Doyle May 29, 1951 

